Requirements for the high reliability of a system have gradually increased. In one regard, higher-layer software asks the system to store some data before reboot. In this way, the system can read the data after reboot, so as to rapidly recover operation data and further decrease the shutdown time of the system.
In a general purpose computer system, such as a PC or a server, a non-volatile memory, for instance, a disk and a data card, may be used to realize the above function. However, an embedded system (a system which is designed for a specific purpose, e.g. a network device such as a router or switch), may not have such non-volatile memory. Moreover, since the access rate of the disk and the data card is relatively slow, if the disk and the data card are used to realize the above function in a case that high reliability is required and the amount of data is large, the shutdown time of the system will be relatively long.
In a common embedded system, reserved memory is used to realize the above function. The reserved memory is memory reserved by the embedded device for a certain purpose. When the system is initiated, the reserved memory is not managed by a memory management system. The reserved memory has a characteristic of preventing data loss during reboot, and thus can be used to store data which should be reserved before reboot and is to be read when the next reboot, for instance, the data may be reboot information.